Unix Command - pwd

pwd Command (print working directory) is
used to print the name of current working directory from a computer's
command-line interface. If the shell prompt does not already show this, the
user can use this command to find their place in the directory tree. This
command is found in the Unix family of operating systems and other flavors as
well. The DOS equivalent is "CD" with no arguments.

It is a command which is sometimes included built into
certain shells such as sh, and bash. It can be implemented easily with the
POSIX C functions getcwd() and/or getwd().